EP1038618B1 - Tool head for a lathe - Google Patents

Description

The invention relates to a tool head according to the preamble of claim 1.

One already knows a tool head of the type mentioned above, the by means of a positioning radial to the axis of rotation the workpiece holder of the lathe on the disc-shaped Workpiece is positionable. At the beginning of the turning of the Workpiece, which may for example be a brake disc is the workpiece head with the working tools in working position by means of the positioning device on the outer edge of the positioned to be machined area of the workpiece. Subsequently be the both sides of the rotating, disc-shaped workpiece arranged processing tools by a relative movement between the tool head and the workpiece from the outer to the inner edge the surface areas of the workpiece to be machined in Feed direction moves. The editing tools are working each on one of the opposite processing surfaces the workpiece, so that this simultaneously on both working surfaces is being shot. When the editing tools are on inner edge of their respective associated processing surface arrived, one of the two processing tools by means of lifted the adjustment of the workpiece. To take off of the second machining tool becomes the tool head as a whole about half the Abhebeweg the first processing tool moved against the lifting direction, so that the processing points the arranged on both sides of the workpiece processing tools then approximately equidistant from the workpiece. The tool head is then opposite to the feed direction of the Retracting tools from the workpiece. There are the machining tools spaced from the workpiece or lifted, causing the formation of spiral grooves in the plan machined surfaces of the workpiece avoided becomes.

To lift the adjustable machining tool from the workpiece is the tool holder holding the machining tool the previously known lathe in the direction of the axis of rotation of the Workpiece relative to the support member from the working position, in the the machining tool engages the workpiece, against the Restoring force of a spring in the take-off position displaced. To the Lifting the machining tool is a hydraulic adjustment provided, which the spring against its spring force pressurized. In this case, the hydraulic adjusting device pressurized in Abhebelage the machining tool and in Working position of the machining tool without pressure. Being in working position the tool holder by the restoring force of the spring against the Lifting direction of the machining tool against a stop the carrier part positioned. By this measure is achieved that at unpressurized hydraulic adjusting the machining tools held in working position by the spring force are so that an operator on the lathe safely Setup work, such as the manual positioning of the Machining tools on the workpiece holders, can perform.

However, the prior art tool holder has the disadvantage that the Adjustable machining tool except through the hydraulic Adjustment also by the while editing the Workpiece acting on the machining tools machining forces can be adjusted. This allows in particular Vibrations occur on the machining tools, the grooves or bumps on the machined workpiece surface result can have. This is especially in a finishing of the workpiece disadvantageous. Such vibrations can especially when the processing tools after longer life have become blunt, so that the editing tools correspondingly larger cutting or machining forces occur. Also it can be adjusted by lifting the adjustable Machining tool from the working position to thickness tolerances come to the finished workpiece.

DE 35 28 437 C2 already knows a tool head of the aforementioned type, in which one of the two sides of the Receiving space for the workpiece arranged tool holder for Lifting one of the processing tools from the workpiece by means of a longitudinal guide in the direction of the axis of rotation of the workpiece displaceable relative to the other tool holder on the support part of the tool head is arranged. To lift the editing tool is the sliding part of the longitudinal guide with a on a rotationally driven by means of a servomotor ball screw arranged ball nut connected. Also with this Previously known tool head can due to the practically unavoidable Axial play of the ball nut on the ball screw During the machining process, vibrations on the machining tools occur. Unfavorable is also that the adjustment the tool head is constructed comparatively complicated.

There is therefore the task of a tool head of the beginning called type to create a turning of the workpiece with high processing quality and dimensional accuracy. In particular, a scoring on the working surfaces of the workpiece can be avoided.

The solution of this task successful through the combination of features of claim 1.

The direction of rotation of the workpiece holder is thus oriented that at befindlichem in working position, on the workpiece attacking machining tool from the workpiece to the Editing tool exerted the pivoting Workpiece holder against the lifting direction of the machining tool positioned against the stop of the support member. Of the pivotable tool holder and the machining tool held thereon are thereby during the turning of the workpiece firmly positioned on the support member. A lifting of the swiveling Machining tool from the work situation and associated Vibrations on the adjustable machining tool, the grooves could result in the working surfaces of the workpiece, are thus avoided. Because the pairs of the workpiece attacking editing tools firmly positioned to each other In addition, thickness tolerances are machined on the disc-shaped workpiece avoided. The tool head allows Therefore, a turning of the workpiece with high quality machining, Dimensional accuracy and repeat accuracy.

A particularly advantageous embodiment of the invention sees before that the processing point of the pivotable machining tool in the working position of the through the pivot axis of the pivot bearing and the axis of rotation of the workpiece holder or a to the axis of rotation parallel axis spanned plane is spaced. The in a right angle to the pivot axis arranged level extending connecting line between the Processing point of the pivotable machining tool and the pivot axis is then oblique to the axis of rotation of Workpiece holder or the workpiece arranged so that the pivotable tool holder for lifting the machining tool from the workpiece only a relatively small angle must be pivoted. Nevertheless, a comparatively reached a large Abhebeweg.

It is advantageous that the pivotable tool holder means a particular hydraulic adjustment against the Restoring force of a spring from the working position in the Abhebelage is adjustable. Held on the pivotable tool holder Machining tool is then at non-pressurized hydraulic Adjustment drive by the restoring force of the spring in working position positioned so that an operator at unpressurized adjustment Carry out setting-up work on the machining tools without danger can. The hydraulic adjustment can easily be actuated by means of a hydraulic valve, for example via a digital output of the machine control unit Lathe can be controlled. The tool head can thereby especially good with manually operated lathes that are not have a web-programmed CNC control combined become. In particular, older lathes that are still in large numbers are present in the factories, with the tool head be retrofitted.

It is intended that the Swivel mounting of the adjusting device into a storage cavity engaging the carrier part, preferably in rolling bearings having bearing journal, which at one of its axial ends carries the pivotable machining tool, and that on this Bearing pin of the adjustment engages. The carrier part can then be formed as a one-piece housing part, which is the two arranged on both sides of the receiving space for the workpiece Connecting tool holder with each other. The editing tools are then positioned even more precisely in working position.

In an advantageous embodiment of the invention provided that the bearing journal circumferentially a receiving recess has, in which a transverse pin is inserted, with one over the lateral surface of the journal projecting free End forms a counter-attack, the working position of the pivotable Processing tool against the first stop and / or in Take-off position of the pivotable machining tool against the second stop of the carrier part is positionable. The Indian Lagerhöhlung the carrier part mounted bearing pin allows a particularly good support during during turning of the Workpiece on the pivotable machining tool attacking Lateral forces. The transverse pin is preferably in one to the pivotable machining tool adjacent area arranged to support a possible torsionally rigid support of Processing tool against the stop of the support member to to reach.

In an advantageous embodiment of the invention is provided that the first, in working position of the pivotable machining tool at the counter stop fitting stop and / or the second, in Abhebelage the machining tool on the counter-stop fitting stop of the support member by a in their Thread length adjustable stop screw is formed. The Swivel position of the adjustable workpiece holder in the working and / or levering position of the machining tool can then be simple Way by adjusting the Einschraublänge the respective Stop screw can be adjusted, for example, to the Working and / or levering position of the pivotable machining tool to adapt to workpieces with different dimensions

The journal carries a drive pinion, for pivoting the machining tool with a Rack of the adjusting drive meshes. This results in a particularly compact tool head.

Furthermore, it is envisaged that the bearing journal facing away from the end of the rack with a Reciprocating piston is connected to a druckbeaufschlagbaren Working space adjacent that the reciprocating against the spring, in particular a diaphragm spring is supported and pressurized by the Working space against the spring force of this spring from a rest position is displaceable in a working position. This results from the Spring a simply built adjustment with a one-sided pressurized hydraulic piston.

In a particularly advantageous embodiment of the invention are the first and / or second stop, the pivot bearing and / or the adjusting drive in a particular against dust and / or liquids sealed inner cavity of the support member arranged. This will cause positioning inaccuracies of the pivotable machining tool and / or vibrations to the Editing tools, for example, by between Stop and counter stop dust, chips or the like Pollution can be caused reliably avoided.

Fig. 1

eine Seitenansicht eines Werkzeugkopfs mit beidseits eines im Querschnitt dargestellten, scheibenförmigen Werkstücks angreifenden Bearbeitungswerkzeugen,

Fig. 2

eine Unteransicht des Werkzeugkopfs gemäß Fig. 1 mit in Arbeitslage befindlichen, an dem Werkstück angreifenden Bearbeitungswerkzeugen,

Fig. 3

eine Darstellung ähnlich Fig. 2, wobei jedoch eines der Bearbeitungswerkzeuge von dem Werkstück abgehoben ist,

Fig. 4

eine teilweise im Schnitt gehaltene Seitenansicht eines Werkzeugkopfs ähnlich Fig. 1,

Fig. 5

eine Ansicht auf den Werkzeugkopf aus der in Fig. 4 mit V bezeichneten Richtung, wobei verdeckte Kanten strichliniert dargestellt sind,

Fig. 6

eine Aufsicht auf den in Fig. 4 dargestellten Werkzeugkopf, wobei dieser teilweise im Querschnitt dargestellt ist und

Fig. 7

eine Ansicht auf den Werkzeugkopf aus der in Fig. 4 mit VII bezeichneten Richtung, wobei der Werkzeugkopf teilweise im Querschnitt dargestellt ist und verdeckte Kanten strichliniert angedeutet sind.

Embodiments of the invention are explained in more detail with reference to the drawing. Show it:

Fig. 1

3 shows a side view of a tool head with machining tools acting on both sides of a disk-shaped workpiece shown in cross-section,

Fig. 2

1 is a view of the tool head according to FIG. 1 with machining tools acting on the workpiece, FIG.

Fig. 3

a representation similar to Figure 2, but with one of the processing tools is lifted from the workpiece,

Fig. 4

a partially sectioned side view of a tool head similar to FIG. 1,

Fig. 5

4 shows a view of the tool head from the direction indicated by V in FIG. 4, wherein hidden edges are shown in dashed lines,

Fig. 6

a plan view of the tool head shown in Fig. 4, wherein this is partially shown in cross section and

Fig. 7

a view of the tool head from the designated in Fig. 4 with VII direction, the tool head is partially shown in cross section and hidden edges are indicated by dashed lines.

A lathe does not have a closer in the drawing illustrated workpiece holder for a disc-shaped workpiece 1, which is rotationally driven with respect to a rotation axis 2. The workpiece 1 may, for example, a brake disc or a Flywheel for a combustion engine. The lathe has a tool head 3, which has a support part 4, the two, each a machining tool 5a, 5b holding tool holder 6a, 6b carries. For both-sided and simultaneous turning of the disk-shaped workpiece 1 are the machining tools 5a, 5b on both sides of a receiving space 7 for the workpiece. 1 arranged.

The tool head 3 has a plug-in coupling 8, which is detachable with a matching, in particular arranged on a tool turret Recording the lathe is connectable. At the in the drawing the embodiments shown, the plug-in coupling extends 8 each parallel to the axis of rotation of the workpiece or the Workpiece holder of the lathe. Of course, the Connection but also in a different direction and execution to Be arranged rotation axis, in particular at right angles thereto.

By means of a positioning of the tool head 3 is a total in the direction of the axis of rotation 2 relative to the workpiece holder both transverse to the axis of rotation 2 in the by the double arrow Pf1 marked feed direction of the processing tools 5a, 5b, as also parallel to the rotation axis 2 in the feed direction Pf2 displaceable.

The tool holder 6a holding the machining tool 5a is for Lifting the working position located on the workpiece. 1 engaging machining tool 5a from the workpiece 1 by means of an adjustment of the working position in a Abhebelage brought in which the machining tool 5a of the workpiece 1 is arranged at a distance. The adjusting device has to a pivot bearing 9, by means of which the tool holder 6a together with the machining tool 5a held thereon by one in a plane orthogonal to the axis of rotation 2 extending, from the processing point 11a of the machining tool 5a spaced pivot axis 10 relative to the support member 4 is mounted pivotably.

The carrier part 4 carries a stop 12 designed as a stop screw, against which the pivotable tool holder 6a can be positioned with a counter stop 13 counter to the lifting direction of the processing tool 5a in the working position. As can be seen particularly clearly from FIG. 2, the direction of rotation of the tool holder holding the workpiece 1 is oriented so that the machining force F _c acting on the machining tool 5a during the turning process at the machining point 11a abuts the counter-abutment 13 of the tool holder 6a against the stop 12 of the tool holder 6a Carrier part 4 presses. The machining tool 5a is thereby positioned on the workpiece 1 with great accuracy during the turning operation. In particular, vibrations of the machining tool 5a during the turning operation of the workpiece 1 are avoided.

The pivot bearing 9 of the adjusting device has a in one Bearing cavity of the support member 4 held in bearings 14 Bearing 15 on, at one of its axial ends in a direction the pivot axis 10 slidably mounted and secured Sleigh part 16a carries. By means of the slide member 16 a, the Processing tool 5a in the direction of the double arrow Pf1 designated direction of the pivot axis 10 relative to the support member 4 are positioned. The positioning of the Processing tool 5a preferably so that this same Distance from the axis of rotation 2, as the machining tool 5b. The slide member 16a is by means of retaining screws 18 on the Bearing journals 15 can be clamped.

The tool holder 6b has a direction parallel to the axis of rotation 2 of the workpiece holder to the support member 4 slidable Slide part 16b, by means of which the thickness b of the finished machined disc-shaped portion of the workpiece 1 adjustable is. The slide member 16b carries a clamp holder 17, with the the machining tool 5b against the slide member 16b clamped is. By means of retaining screws 18, the slide member 16b in turn Can be fixed to the support part 4. The processing tools 5a, 5b So are by means of the slide parts 16a, 16b in transverse to each other extending directions relative to each other positionable.

On the slide parts 16a, 16b are each clamp holder 17th attached, with which the respective machining tool 5a, 5b, the for example, an insert may be on the tool holder 6a, 6b can be fixed.

As can be seen particularly clearly from FIG. 2, the processing point is 11a of the pivotable machining tool 5a in FIG Working position of the through the pivot axis 10 of the pivot bearing 9 and one parallel to the rotation axis 2 of the workpiece 1 Spaced plane axis spaced. The bearing pin 15 needs thereby lifting the machining tool 5a from the workpiece 1 to be pivoted only by a small angle.

In Fig. 4 it can be seen that the bearing pin 15 at its Outer circumference has a receiving recess into which a transverse bolt 19 is inserted, with a laterally on the bearing journal 15th protruding free end against the stop 12 of the support member 4 positionable counter-stop 13 forms. In Fig. 4 can be seen that the transverse pin 19 in a tool-near area between the arranged as two tapered roller bearings rolling bearings 14 is. As a result, a high flexural rigidity of the support is achieved. For adjusting the pivot position of the tool holder 6a in the Working position of the machining tool 5a is the stop 12th forming stop screw in its thread length adjustable. The stop screw is with a threaded hole of the Carrier part 4 screwed, in which they outside of the support member 4 is accessible.

The bearing pin 15 carries on its outer circumference a drive pinion 20, which is for pivoting the machining tool 5a between the working and the Abhebestellung with a rack 21 of the Adjustment drive is engaged. That the journal 15 opposite end of the rack 21 is connected to a reciprocating piston, which is arranged in a working cylinder and a pressurizable Working space 23 limited. This one is over a channel 24 connected to a print source. At the working space 23 opposite side of the reciprocating piston 22, a spring 25 is arranged, the one with the end facing away from the working space 23 back of the reciprocating piston 22 and with its other axial end against the Carrier part 4 is supported. By pressurizing the Working space 23 is the reciprocating piston 22 from a rest position in the the pivotable by means of the reciprocating piston 22 machining tool 5a is arranged in working position and acts on the workpiece 1, against the restoring force of the spring 25 in a working position slidably, in which the machining tool 5a of the workpiece 1 is lifted. Thus, the tool holder 6a is depressurized Working space 23 by the restoring force of the spring 25 with the Counter stop 13 positioned against the stop 12 of the support member 4, i.e. the machining tool is in working position. An operator can thereby at pressure-free reciprocating 22 safe setup work on the tool holders 6a, 6b carry out. For example, the editing tools 5a, 5b exchanged and / or by means of the slide parts 16a, 16b be positioned on the receiving space 7 for the workpiece 1. It should also be mentioned that the spring 25 as a plate spring with a plurality of annular spring elements arranged in a stack is formed and that the rack 21 that of the annular Spring elements bounded opening of the spring 25 passes. Thereby This results in a particularly compact tool head 3.

The support part 4 is formed as a housing with an inner cavity, which is sealed to the outside. In the inner cavity are the Drive pinion 20, the rack 21, the counter-stop 13 and the Stop 12 against outside of the housing located dusts and / or Liquids protected arranged. A pollution of these parts as well as associated mispositioning of the machining tool 5a, the workpiece holder 6a and vibrations and the like Instäbilitäten the tool head 3 during the turning of the Workpiece 1 can be avoided.

The following is the procedure for turning the Workpiece 1 explained. At the beginning of the processing is the Tool head 3 with the working tools located in working position 5a, 5b positioned on the workpiece 1 that the Processing points 11a, 11b of the processing tools 5a, 5b on outer edge of the disc-shaped area to be machined Attack workpiece 1. Subsequently, the tool head in Feed direction Pf1 shifted until the processing points 11a, 11b the inner edge of the area to be machined of the workpiece 1 have reached (Fig. 1). Then, the machining tool 5a by a pivoting movement about the pivot axis 10 of the workpiece 1 lifted off. For lifting the machining tool 5b of the Tool head 3 in total by about half Abhebeweg of Processing tool 5a in the direction of the axis of rotation. 2 shifted, so that the processing points 11a, 11b of the two Machining tools 5a, 5b then approximately equidistant from the workpiece 1 are spaced. Thereafter, the tool head 3 against the Feed direction withdrawn from the workpiece 1.

It should also be mentioned that the lathe according to the invention can also be designed as an inclined bed machine. Possibly the tool head 3 can also be arranged on a robot arm.

Claims (6)

1. Tool head (3) for a lathe which comprises a workpiece holder, rotationally driven about a rotation axis (2), for a disc-shaped workpiece (1), the tool head (3) having a carrier part (4) with at least two tool holders (6a, 6b) each holding a machining tool (5a, 5b), the machining tools (5a, 5b) being arranged on both sides of an accommodating chamber (7) for the workpiece (1) for simultaneous rotary machining of both sides of the disc-shaped workpiece (1), while at least one of the tool holders (6a) holding a machining tool (5a) is movable by means of a displacement device having a displacement drive in order to lift the machining tool (5a) away from the workpiece (1) from a working position into a retracted position, the displacement drive having a lifting piston (22) which is adjacent to a working chamber (23) adapted to be subjected to pressure and which bears on a spring (25), said lifting piston being movable from a resting position into a working position as the result of the application of pressure to the working chamber (23) counter to the spring force of the spring (25), characterised in that the displacement device has a pivot mounting (9) for the tool holder (6a) associated therewith, by means of which the machining tool (5a) held thereon is mounted to be pivotable, relative to the carrier part (4), about a pivot axis arranged transversely with respect to the rotation axis (2) and spaced from the machining point (11a) of the machining tool (5a), in that the pivot mounting (9) has a mounting pin (15) engaging in a mounting cavity in the carrier part (4), said pin carrying the machining tool (5a) at one of its axial ends, in that the mounting pin (15) carries a drive pinion (20) which meshes with a rack (21) in order to pivot the machining tool (5a), the end of said rack remote from the mounting pin (15) being connected to the lifting piston (22), and in that the carrier part (4) has at least one abutment (12) against which the pivotable tool holder (6a) can be positioned in the operating position by means of the machining force acting on the pivotable machining tool (5a) during rotary machining, counter to the direction of retraction of the machining tool (5a).
2. Tool head according to claim 1, characterised in that the machining point (11a) of the pivotable machining tool (5a) in the operating position is spaced from the plane set by the pivot axis (10) of the pivot mounting (9) and the rotation axis (2) of the workpiece holder (9) or an axis parallel to the rotation axis (2).
3. Tool head according to claim 1 or 2, characterised in that the carrier part (4) in addition to the first stop (12) against which the pivotable tool holder (6a) can be positioned in the operating position has a second stop against which the tool holder (6a) can be positioned in the raised position in the direction of retraction of the machining tool (5a).
4. Tool head according to one of claims 1 to 3, characterised in that the bearing pin (15) comprises on the circumferential side a receiving recess into which a transverse bolt (19) is inserted which forms, with a free end projecting over the outer surface of the mounting pin (15), a counter-stop (13) which can be positioned against the first stop (12) in the operating position of the pivotable machining tool (5a) and/or against the second stop of the carrier part (4) in the raised position of the pivotable machining tool.
5. Tool head according to one of claims 1 to 4, characterised in that the first stop (12) abutting on the counter-stop (13) in the operating position of the pivotable machining tool (5a) and/or the second stop of the carrier part (4) abutting on the counter-stop (13) in the raised position of the pivotable machining tool (5a) is formed by a stop screw which is adjustable in its length of engagement.
6. Tool head according to one of claims 1 to 5, characterised in that the first stop (12), the second stop, the pivot mounting (9) and/or the displacement drive are disposed in an inner cavity in the carrier part (4) which is sealed off particularly against dust and/or liquids.

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